For example, in a general regional broadcast radio system (or a regional simultaneous communication system), a master station is installed in an administrative agency, and a plurality of terminals are installed outside or inside of facilities in the administrative district administered by the agency, so that notification information such as disaster-related information is transmitted by radio from the master station to those terminals.
The broadcast radio systems are provided on an administrative district (e.g., country, town or ward) basis and communication from the master station to the terminals are carried out by radio. Therefore, when same broadcast radio systems are operated in neighboring districts (or regions), there may occur crosstalk interference of radio waves between broadcast radio systems in the districts. Because of this, as a measure for preventing such a crosstalk problem, there is a control operation, in which different frequencies are allocated to different broadcast systems and a district (or region) district code is transmitted as a scramble code when transmitting information by radio. In such a central operation, if the scramble code in the notification information received by a terminal does not coincide with a pre-registered scramble code therein, information reception is not executed. Hereinafter, a broadcast radio system between a master station and a terminal which are originally belong to a same district will be referred to as a “intra-broadcast radio system”, and a broadcast radio system between a master station and a terminal in different districts will be referred to as an “inter-broadcast radio system”.
FIG. 6 illustrates an example of a configuration of a digital regional broadcast radio system 200.
In FIG. 6, components that are similar to those shown in FIGS. 1A and 1B related to an embodiment of the present invention to be described later are given the same reference characters. The regional broadcast radio system 200 shown in FIG. 6 includes, e.g., a master station E, and a plurality of terminals which include plural terminal stations F1-Fn, and a number of house receivers G1-Gm.
The master station E includes a base station radio transceiver 1 having a controller 11, a radio unit 12, and an antenna 13 to execute radio communication; an operation table 2 for operating in response to a command to receive various kinds of instructions; and a text transmitter 3 for operating in response to a command to execute the input of text messages and the transmission of text.
Each of the terminal stations F1-Fn includes a terminal station main body 21 having a controller 31, a radio unit 32, and an antenna 33 to execute radio communication; a connection box 22 functioning as an interface for connecting the terminal station main body 21 with other components 23 and 24; a horn speaker 23 outputting sound including alarm and/or voice, in response to a command; and a display 24 displaying text information and the like in response to a command. Each of the house receivers G1-Gm includes a display unit 41 for displaying information and the like.
In the regional broadcast radio system 200, for example, if a terminal under in the intra-broadcast radio system tries to receive notification information from the inter-broadcast radio system, the reception frequency and the district code of the terminal state device under the intra-broadcast radio system are changed by those for the inter-broadcast radio system, so that the terminal under the intra-broadcast radio system can receive the notification information in the inter-broadcast radio system.
[Non-Patent Document 1] regional digital simultaneous communication system, ARIB STD-T86, Association of Radio Industries and Businesses (http://www.arib.or.jp/english/html/overview/doc/1-STD-T86v3—0.pdf)
In an emergent disaster where the digital regional broadcast radio system is most frequently used, a terminal under the intra-broadcast radio system is occasionally lent out to inter-broadcast radio system, so that disaster information of a neighboring district can be acquired. In this case, according to the technique disclosed in the Non-Patent Document 1, a worker personally must change the set-up by following the complicate set-up procedure, which takes a certain amount of time (several minutes). Because of this, immediate responses and fast actions are difficult to be performed. Further, as a fire fighting radio system, for example, disaster recovery activities across administrative districts (e.g., country, town or ward) and the like, are required as countermeasures of emergent disasters. Also, the regional broadcast radio system is required not only for transmitting information within the intra-broadcast radio system, but also for receiving notification information from inter-broadcast radio system. Therefore, there is a need for a function of providing all local residents with notification information such as proper, accurate information related to disaster and the like.